To establish the relationship between EEG sleep, sympathetic tone and immune function, to characterize the nocturnal secretory profile of lymphokines, neuroendocrine hormones and neurotransmitters, to examine nocturnal secretion of lymphokines, hormones and catecholamines in psychiatric patients with sleep disturbance, and to test link between sleep, neuroendocrine and sympathetic measures and immunologic responses using partial sleep deprivation.